November 27, 2008

We warned you that the Awesome was coming … now it’s here. The first installment of Awesome, anyway, and there’s plenty more to come.

Matt and I have just returned from a nine-day trip to Germany that was pretty much Heaven-on-Earth for us. The first three days were spent in Bonn, at the first open workshop of the DFG-funded Biology of the sauropod dinosaurs: the
evolution of gigantism project. Happily, Matt and I were each able to give two talks: his on the sauropod lung and the repeated evolution of very long necks, mine on limb-bone cartilage strength and habitual neck posture. (There is a lot more to say about this workshop, which was fascinating for all sorts of reasons, but I am going to press quickly onwards because you want to get to the pictures.)

After the workshop proper came a three-day field-trip, which took us first to the Dinopark at Münchehagen, where we saw the quite startling Europasaurus material, then to the Langenberg Quarry where Europasaurus is found, and finally to Berlin, home of the Humboldt Museum für Naturkunde and therefore also of Brachiosaurus brancai (at least, since it was dug up in Tanzania and sent there). Matt and I, and Mike D’Emic, stayed on for two further days after the field-trip’s visit to the Humboldt, to work on the Tendaguru sauropod material.

Soon we’ll show you some of the great stuff in the collections, but for now I want to concentrate on the public gallery. It’s three years since, at SVPCA 2005, I described this gallery’s brachiosaur mount as “the single finest object in the known universe”, and that was true even then. But now the glorious material has been remounted by RCI, under the supervision of Kristian Remes, in a more anatomically correct and far more dynamic pose, and it’s better still. (The photo at the top shows the remounted brachiosaur, with me for scale next to its elbow. I bet you didn’t even notice me there when you first looked at it.) Not only that, but Dicraeosaurus has also been remounted, along with the museum’s cast of the Carnegie Diplodocus (standing in for the Tendaguru diplodocines Tornieria and Australodocus), so that the three sauropods together make a stunning display of Tendaguru sauropod diversity. (There’s a picture of the whole exhibit at the end of this post). This is so awesome that I have had to revise my previous opinion that the public gallery of the OUMNH is my favourite in the whole world. It is now an honourable second.

The Humboldt staff were very good to us, and allowed us quite a bit of quality time alone with the mounts, in the mornings before the public arrived and in the evenings after they’d gone. Not only that, but they equipped us with a stepladder and a pair of arsegravies to stand it on, so it wouldn’t damage the exhibit’s floor covering — so we were able to get close to the material. Here, for example, is Matt, carefully checking the proximal caudals for [REDACTED], with Dicraeosaurus‘s head and neck in the background:

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Better still, I was able to get right up inside the brachiosaur’s torso, which I needed to do in order to measure its girth:

(There was no possible way to run a tape measure across the rib-cage without a second ladder, so I had to drop lines to the ground: Matt marked where they fell, then measured the distance between the marks. Brachiosaurus brancai is A LOT bigger than Diplodocus.)

When palaeontologists gather around a mounted skeleton, it’s traditional to pick holes in the mount: in extreme cases, you can find silly mistakes like the scapulae being mounted upside down (juvenile Mamenchisaurus casts at the FMNH), but there is always something to criticise. Well, almost always, it turns out. Matt and I stared at that brachiosaur mount pretty intensely for three days, and we came up with, basically, nothing. Kristian and RCI did a great job on it: it’s completely convincing not only as a piece of skeletal anatomy but also as an animal. It looks alive. (After a while I did manage to come up with one criticism: the most posterior cervical ribs are too long and thin. But that’s all I’ve got.)

Finally, here is that whole-exhibit photograph that I promised you. In case you need to be told, the brachiosaur is the big one, Diplodocus is to the right, and poor little Dicraeosaurus is half-hidden off to the left, behind the big fella.

(Sorry about the glass refections in this photo: it was taken from a room that has been fitted with unopenable windows, so I think this is unavoidable. Also sorry that the head is out of focus. To fit the whole exhibit in, I had to use a wide-angle lens, and it distorts the edges of the picture.)

In future Shedloads of Awesome posts, we’ll show you Dicraeosaurus in more detail, some of the Awesome down in the collections (including the brachiosaur skull, if we can find a way to fit something so off-topic into SV-POW!), and maybe, if you’re luckly, some of that Europasaurus material.

November 22, 2008

If you’ve been following SV-POW! closely – perhaps a little too closely – you will know of BMNH R5937, a Tendaguru sauropod collected in 1930 on one of the British Museum (Natural History) expeditions, and reported in 1931 by Frederick Migeod (pronounced ‘mee-zhou’). Discovered in the ‘M23′ quarry at Tendaguru, the specimen was assumed by Migeod and all subsequent authors to be another specimen of Brachiosaurus brancai, but what’s notable is that Migeod mentioned several features in the vertebrae of the specimen that really sounded quite un-Brachiosaurus-like. Despite the size and quality of the specimen however, nobody ever got round to studying it properly – until Mike did exactly this. An abstract and talk slides on the specimen can be found here. For whatever reason, the specimen has become known as The Archbishop.

While Migeod wrote about The Archbishop, he never published any illustrations of it (with the exception of a quarry map). I don’t think I’m betraying any secrets by letting on that Mike is working on a full technical desciption of the specimen, wherein it will of course be illustrated properly. Little known however is that The Archbishop has appeared in the literature before, but (unsurprisingly, and in keeping with tradition) has been misidentified as Brachiosaurus. After all, it’s a big sauropod and it comes from Tendaguru, so it must be Brachiosaurus, right? Here’s the proof: it’s p. 94 of David Lambert’s Ultimate Dinosaur Book, published by Dorling Kindersley in 1993. The Archbishop photo is, of course, up there at top right, masquareding as the dorsal vertebrae of Brachiosaurus brancai.

November 12, 2008

I’m worried that you might be getting spoiled, only getting to see perfect beautiful vertebrae, so I’m gonna show you some uglies now and then just to keep the universe in balance.

As uglies go, this one ain’t bad. It’s clearly a cervical, probably from Camarasaurus, given how far the prezyg overhangs the front of the centrum. As I recall, the internal structure on this one is pretty gorgeous, which illustrates a paradox that Kent Sanders and I discovered: many times the verts that are ugliest on the outside have the most beautiful internal structures, whereas verts that look nice on the outside are sometimes unreadable mush within.

Or rather, the internal structure of this vert would illustrate that paradox, if I could show it to you. But nice as it was, this was never one of my worth-publishing-on specimens, and although I know the CTs are around here somewhere, I can’t pinpoint their location right now. It’s a Heisenberg thing.

November 8, 2008

I just got word from the History Channel that their documentary “Evolve: Size” will air Saturday, Nov. 8. Kent Sanders, Brooks Britt, and I filmed a long segment for this back in May, covering pneumaticity in sauropods. Hopefully it didn’t all go to the cutting room floor! With any luck, you’ll see the results of this:

Check local listings for showtimes.

UPDATE: IMMEDIATE REACTION

Hey, not bad. Good stuff:

I especially liked that they ascribed the evolution of large size in sauropods to several factors–high plant productivity, efficient food gathering (just biting, no chewing), and, yes, pneumaticity. But pneumaticity was at best an accessory adaptation for large size, and not a prime mover. I was worried that its importance would be overstated–“AIR-FILLED bones made these GIANTS into the HUGEST creatures EVAR!!1!” That’s some impressive restraint for a documentary these days.

The bit about pneumatic bones being light but also strong is great. I’m glad they worked in the pneumatic horns of bighorn sheep.

I’m really happy that they showed the process of CT scanning the vertebra, partly because It’s never been shown before on TV (to my knowledge), and partly for purely selfish reasons: it’s just cool. Too bad they didn’t have time to show Kent Sanders discussing the results of the scan.

Some clarifications:

Brooks Britt is not a grad student now, he’s an Associate Professor of geology at BYU. He pioneered the use of CT to study pneumaticity in dinosaurs when he was a grad student at the University of Calgary (Britt 1993). I am glad that they got the bit in about Brooks first suggesting to me that I should CT scan sauropod vertebrae. He got me into this, and it’s nice to have that recognized.

At one point the narrator says, “Wedel suspects that the bones were not only light and easy to lift, they also helped get oxygen directly to the muscles, fed by a system of air sacs throughout the neck, similar to birds today.” Woof–I didn’t say that! They got the ventilatory air sacs in the thorax and abdomen–the ones that blow air through the lungs–confused with the pneumatic diverticula up in the neck. There is no evidence that diverticula play any role in gas exchange for the tissues they are adjacent to, and there is strong contrary evidence. Physiologists have measured how much gas exchange goes on in the avian respiratory system, and where that gas exchange occurs. Ninety-five percent of the gas exchange happens in the lungs, and almost all of the remainder happens in the abdominal air sacs, which are immense and fairly convoluted because they enclose the viscera like a nut-shell (thanks to Wetherbee [1951] for that wonderfully accessible image). It’s a fairly minor thing, I guess, it’s just frustrating to spend so much time working on this and then have an obvious mix-up like that sneak in.

In the space of about ten minutes, sauropods are described as “freaks of nature” twice! This is a bit irritating–they are only freaks of nature from our limited, human point of view. Big sauropods had appeared by the late Triassic and huge ones by the Early Jurassic, and they stayed huge and successful through the Jurassic and Cretaceous. For all that they were immense and morphologically derived, sauropods were also just critters. They weren’t mutants, they were functioning and apparently successful members of their ecosystems for a long time, like any other organisms. Possibly, though, long exposure has acclimated me to the just-critters aspect of sauropods more than most folks. :-)

It seems churlish to write so much about a segment that was actually pretty great and right on target except for a few, comparatively minor missteps. Overall I’m thrilled that it turned out so well. See it if you get a chance–your own thoughts are welcome, good, bad, or otherwise.

November 6, 2008

Today, we bring you the long-overdue third installment in everyone’s favourite Mystery Sauropod Dorsals serial, our trawl through the NHM’s collection of mostly isolated elements from the Wealden Supergroup.

Many of these elements are too bashed up to be diagnostic (with the Xenoposeidon holotype R2095 being an honourable exception). But there are one or two that are much better preserved, and arguably the best of these are the pair of elements BMNH R88/R89, which in some sense belong to “Eucamerotus” (read on). These are difficult to photograph well, because they are in a glass case in the public gallery, but fortunately Hulke (1880: plate IV) illustrated the more anterior and better preserved of the two:

Like far too many British sauropod specimens, this one is mired in a taxonomic hell-hole. It was described by Hulke as belonging to Ornithopsis, a genus based on a horribly non-diagnostic type specimen, and it is this name that appears on the exhibit label (along with the incorrect specimen numbers R89/90 … oh well, One Out Of Two Ain’t Bad.)

Here is my least bad photo of R88 and R89, in left lateral view, with R88 on the left:

Blows (1995) referred this pair of dorsals, and a bunch of other specimens, to another ancient British name, Eucamerotus — in fact, he nominated them as paratypes — but didn’t give any reason for doing so. (He also referred to the R88/R89 pair jointly as R90, thus further muddling the specimen numbering.) Blows’s reassignment to Eucamerotus is puzzling, because while the Eucamerotus type specimen is also pretty undiagnostic, consisting only of a partial neural arch, it does have one obvious apomophy, which is huge robust parapophyses supported on what I like the call The Prezygaparapophyseal Laminae Of Doom. (Remind me to show you this specimen some time.) That feature, of course, R88 and R89 completely lack.

So what are they? I don’t think they can be referred with any confidence whatsoever to either Ornithopsis or Eucamerotus, two questionable genera of which at least the first is invalid. So perhaps the right thing to do would be to torpedo those names and raise R88/89 as the type specimen of a new taxon? There’s more work to do before taking such a step, not least an exhaustive trawl through the historical literature, but I think that might eventually prove the way to go.

Based on general proportions and overall “gestalt”, these vertebrae appear to be brachiosaurid — but I put them in a cladistic analysis a while back (so far unpublished) and they didn’t clade unambiguously with Brachiosaurus, so we’ll have to see how that develops when I finally get around to adding my thirty-odd new characters of the dorsals. Don’t hold your breath. At least, these elements are much more convincingly brachiosaurid than anything else I’ve seen from the Wealden. So do they consitute Britain’s best brachiosaur?

Well, maybe. Not if you count The Archbishop, Migeod’s Tendaguru brachiosaur, which I’ve been working on for waaay too long now, but really, really will describe Real Soon Now. (Amazingly, this specimen has yet to appear on SV-POW!, unless you count my T-shirt in one of the photos of our Oxford Museum visit.) But since this specimen is from the Tendaguru Formation of Tanzania, it should probably be discounted from the BBB competition.

In fact, Britain’s Best Brachiosaur is probably the “Barnes High Sauropod” from the Isle of Wight. But that’s in private hands and the ownership/availability situation is complex. For that reason, no-one has yet published on it, and in fact I have never seen any of the material except what’s embedded in a wall-mount at Dinosaur Isle. I’m not sure what’s happening with this specimen (I don’t think anyone is) but if I ever get a chance to find out, I will!

References

Blows, William T. 1995. The Early Cretaceous brachiosaurid
dinosaurs Ornithopsis and Eucamerotus from the Isle of
Wight, England. Palaeontology 38 (1): 187-197.